I was prescribed nitrofur-macr 100 mg for a uti, and I take the birth control Sprintec. Does this certain antibiotic affect my birth control? My doctor gave me no warnings about it affecting my birth control and he didn't say to use a backup plan if I was planning on having sex, so I had no idea that antibiotics affect birth control until now.

Good news. They don't.

The only antibiotic that's been shown to interfere with birth control is rifampin (so unless you have TB you probably won't be using it any time soon). If anything, there may be some decreased effectiveness of the antibiotic, but I'm sure your doctor took that into account. And even if they didn't this is negligible for most healthy people. So no worries.

But, using a condom never hurt anyone.

;-)